According to Casey Hudson, BioWare tried to improve every part of Mass Effect 2 from the first Mass Effect, especially combat. The game feels like a precision shooter with accurate and powerful weapons, and there are also physics-based special abilities that can be fired in real time.In combat, players have regenerating health, but cannot heal themselves with medi-gel like in the first Mass Effect; however, medi-gel can still be used to revive downed squad mates. The ability to fire a weapon no longer relies on an overheating system; instead, ammunition is used. Ammunition is universal across most standard weapons, unlike in most other third person shooters where different weapons require specific ammunition.